Blow-off indicator



' May 20-, 1924. 1,494.779

J. C. FISCHER BLOW-OFF INDICATOR Filed Dec. 11. 1919 Patented May 20, 1924.

JOSEPH C. FISCHER, OF WAUWATOSA, WISCONSIN.

BLOW-OFF INDICATOR.

Application filed December 11, 1919. Serial No. 344,246.

To all whom it may 0012mm:

Be it known that I, Josnrrr C. FISCHER, a citizen of the United States, residing at VVauwatosa, county of Milwaukee, and State of Wisconsin, have invented new and useful Improvements in Blow-Off Indicators, of which the following is a specification.

This invention relates to blow-off indicators.

In a boiler the usual construction involves a blow-off pipe which is placed at the rear and bottom portion of the boiler and is adapted to be periodically opened by means of a hand valve to allow mud, scale and other sediment to be blown from the boiler by the outgoingstream of water. If these blow-ofit' pipes are not periodically opened, the sediment collects in such pipes and often fills them completely. These pipes are usually exposed to a portion of the furnace heat and in this abnormal condition noted above, they soon become burned through, or cracked and give trouble, often of serious nature. A regular blowing off of the boiler would insure these pipes remaining clean and free from sediment.

A second source of trouble comes from the closing of the watercolumns which indicate the water level of the boiler. Deposit often occurs in these columns and associated pipes to such an extent that the water level is not accurately indicated. A regular blowing off of the water columns is. therefore. a very essential feature in the accurate operation of a steam boiler.

It is to insure the regular blowing off of the various parts of a boiler system that the present invention is designed.

One of the objects of the invention is to provide a blow off indicator which will re cord the time and duration of the blow off periods.

Other objects of the invention are to provide a blow off indicator which is of simple design and may be readily applied to the boiler fittings; to provide electro-magnetic means which are controlled by the blow off indicator and which may be placed at a remote point, as for instance, in the superintendents oflice; to provide a fitting which is adequately housed, thereby protecting the electrical and mechanical parts thereof.

Further objects are to provide an electric switch controlled by fluid pressure in whichsliding or wiping contacts are employed whereby ordinary conducting metal may be used; to provide a combined spring pressed piston and electric switch operated thereby; and to combine the parts in a simple unitary structure which may be readily screwed into a T or other fitting and will thereafter require little or no attention.

An embodiment of the invention is shown in the accompanying drawing. Fig. 1 is a diagrammatic view showing the rear end of a boiler with a blow ofi indicator in position, an electric circuit controlled thereby, and an electromagnetic recording means connected in said circuit.

Fig. 2 is a sectional elevation of the blow off indicator.

While the blow off indicator is shown at tached to the usual drain, or blow off pipe from the boiler, it is to be understood that it may be attached to any exhaust pipe where it is desired to record a rise in pressure.

Fig. 1 shows the boiler 1 which is provided with a blow off pipe 2 which is controlled by a hand valve 3. On the other side of the hand valve 3 from the boiler 1 a T shaped fitting 1 is located, the portion 2- of the blow off pipe extending therefrom and opening to the outside air. The blow off indicator 5 is screwed into the fitting 4 and serves to operate a switch carried in the upper casing 6 of such blow off indicator when the pressure in the pipe 2 rises. This closing of the switch closes the circuit in the electric system 7 and allows the battery 8 to energize the electro-magnet 9 thereby attracting the spring-held armature 10 and moving a recording pen 11 substantially radially across a clock driven dial 152. It will thus be seen that when the blow off takes place, the pen 11 travels towards the center of the dial making a depression 13 in the smooth curve that it has been tracing prior to the blow off. The width of this depression indicates the duration of the blow off and the position of this depression upon the dial indicates the time of the blow off. When the blow off has finished, the pen 11 moves outwardly to its original position and continues tracing a smooth curve upon the dial. These dials may be the twelve or twenty-four hour dials used in recording machines and should be changed regularly so that a complete daily record can be kept of the time and duration of the blow off periods.

. Fig. 2 shows the blow ofi indicator 5 which comprises a cylinder 14 which is open at the lower end and threaded into the fitting 4. The upper end of the cylinder is closed by means of a cap 15 into which the cylinder is screwed. The cap 15 carries a stufting box 16 and a gland 17 whereby packing may be pressed against the piston rod making a substantially gas tight connection. This construction is necessary when it is desired to completely protect the upper portion of th cylinder from dust or fumes.

- The motion of the piston is not interfered and nut 21.

with by this closing of the upper end for the reason that the travel of the piston is small and there is little resultingcompression of the confined air above the piston. When it is not necessary to completely seal the upper end, vent holes may be provided to allow the air above the piston to escape. At its lower end the piston rod 18 is provided with a piston 19 held thereon by a flange 20 The piston is spring pressed downwardly by means of a coiled spring 22 surrounding the piston rod 18 and bearing atone end against the cap 15 and at the other end against the piston 19. The upper end of the piston rod carries a cone shaped contact member 23 which rests in the lowest position upon lugs 24 formed on the upper cap 25 which cap is carried by supporting members 26 from the cylinder 14. The cap 25 has screwed thereto a casing 6 which is closed at its upper end by means of an upper cap 27. Theparts thus far described may be of metal or other suitable material. The cap 27 carries an insulating block 28 which has a cone-shaped recess 29 formed therein. Projecting into this recess are a pair of spring contacts 30 which are so proportioned as to simultaneously contact with .the member 23 when such latter member is in its raised position. This member 23 has a sliding motion relative to the members 30 to thereby wipe over the surface of such members and keep a clean contact surface thereon. The members 30 are connected with insulating block 28 and electrically connected to insulated binding posts 31 by means of bolts 32 which pass through the insulating block-28. The terminals of the system are connected to the binding posts 31 so that when the member 30 and the members 23 contact, the electrical circuit is complete and the battery 8 is allowed to energize the electromagnet 9.

It will therefore be seen that a very simple and durable blow off indicator has been provided which may be readily connected in place by screwing the cylinder into the corresponding fitting and connecting the wires to the binding posts.

The recording mechansm may be placed in the superintendents ofiice if desired, or at some point remote from the boiler, and the functioning of this part of the boiler systern may be, therefore, always directly under the observation of the superintendent.

Obviously other structures may be devised which will embody the invention herein set forth.

I claim:

1. The combination with a boiler and a blow off pipe provided with a valve, of a chamber communicating with said pipe and exterior to said valve, said chamber being removed from the path of material traversing said pipe, and means operative by pressures in said chamber for indicating the blow off of said boiler.

2. The combination with a boiler and a blow off pipe provided with a valve, of a chamber communicating with said pipe, magnetically operable recordingmeans, an electrical circuit arranged to actuate said recording means and including a switch, and a pressure controlled device operative in said chamber out of the path of material traversing said pipe and operatively connected with said switch.

3. The combination of a boiler blow off pipe provided with a valve, a cylinder associated with said blow 0E pipe exterior to said valve, a piston mounted in said cylinder, and means associated with said piston whereby the time and duration of blow off may be recorded by the rise of pressure in said pipe exterior to the valve.

4. Means adapted to indicate the time and duration of blow off of a boiler, said means including the combination. with a blow off pipe of a piston removed from possible contact of material traversing said pipe and exposed pressures therein, a' spring adapted normally to hold said piston substantially in its innermost position, an electrical switch operated by said piston, indicating means, and electromagnetic means associated with said indicating means, whereby the time and duration of the blow oft may be indiconnected into said pipe exterior to the valve, a piston mounted in an arm of said fitting, a spring adapted normally to hold said piston substantially in its innermost position, an electrical switch operable by the movement of said piston, indicating means, and electromagnetic means associated with said indicator, whereby the time and duration of blow off may be recorded by the rise of pressure in said pipe exterior to the valve. 6. The combination with a blow ofl pipe for boilers, of a T -shaped fitting having one of its arms elongated, a cap secured to the outer end of said arm and provided with an opening in axial alignment therewith, a pising, a spring disposed between said piston and said cap and adapted normally to hold said piston in an innermost position, a stationary electrical contact supported from said fitting, an electrical contact mounted upon said rod and adapted, when said piston moves outwardly, to make contact with said stationary electrical contact, recording means, and electromagnetic means associated with said recording means and including an electrical circuit adapted to be closed by said contacts, whereby the time and duration of blow off of fluid passing through said pipe may be recorded.

7. In a blow off indicator, the combina-' tion with a T-shaped fitting adapted to form a continuation of a blow off pipe and having one of its arms elongated, of a cap secured to the outer end of said arm and provided with an opening concentric therewith, a casing supported from said elongated arm and having an opening concentric with the first mentioned opening, a plunger mounted in said arm and adapted to move axially thereof, a rod secured to said plunger and extending through said 0 enings and into the easing, a cone shape member carried by the rod and disposed within the casing, and spring contact members mounted within the casing and extending radially thereof, whereby when fluid is blowing off through said fitting, said plunger will be actuated outwardly by the pressure generated by the blow OE and the cone shaped member will be moved to contact with the contact members to close an electrical circuit.

In testimony whereof I afiix my signature in the presence of two witnesses.

JOSEPH C. FISCHER. Witnesses:

' JOHN Mnssmm,

A. R. WOOLFORT, Jr. 

